Concepts — Redis
Architecture
Redis on Hikube is a managed service. Each cluster created from the console is a master-replicas set, supervised by Redis Sentinel for automatic failover. It belongs to a project and consumes that project's quotas.
Terminology
| Term | Description |
|---|---|
| Redis Cluster | Managed instance created from the console, made up of a master and any replicas. |
| Project | Isolated space that groups your resources and carries the quotas. |
| Master | Main instance that accepts reads and writes. |
| Replica | Read-only instance, synchronized from the master. |
| Sentinel | Supervision process that detects master failures and orchestrates automatic failover. |
| Preset | Resource template (CPU, memory) allocated to each node of the cluster. |
| Public network | Option (also called External access) that exposes the cluster on the Internet through a public IP address. |
| Authentication | Access protection with a cluster-wide password. |
High availability with Sentinel
Redis Sentinel provides high availability by:
- Monitoring the master and the replicas continuously
- Detecting a master failure by consensus among Sentinels
- Promoting a replica to new master automatically
- Reconfiguring the other replicas to follow the new master
The Number of replicas is chosen at creation (from 1 to 8).
Automatic failover works from 2 replicas: three sentinels are always deployed and form the quorum. Choose 3 replicas or more for production, to tolerate more failures.
The number of replicas cannot be changed after creation ("The mode cannot be changed after creation"). To change it, contact support.
Persistence
Each node has a persistent volume whose capacity is set by the Volume size (GB) field ("Storage capacity allocated to each node in the cluster"). Redis writes its data to disk through its native mechanisms, which lets the data survive restarts.
Authentication
The Enable authentication option is on by default in the wizard:
- Enabled: a password is generated at creation and displayed only once, together with the
defaultuser. You can renew it at any time from the Security section of the cluster page (Rotate password). - Disabled: the cluster accepts connections without a password. Avoid this, especially with the public network enabled.
Redis on Hikube does not expose multi-user management (ACL) in the console: access relies on this cluster-wide password.
Network access
- Public network disabled (default, "Private" in the summary): the cluster is not exposed on the Internet. The Connection section of the cluster page shows "Waiting for allocation..." instead of the host.
- Public network enabled ("Public"): the platform assigns a public IP address, displayed in the Host field. It gives access to the master on the standard Redis port,
6379, and follows the master after a failover.
Presets
The Preset defines the capacity allocated to each node of the cluster. Presets are the virtual machine sizes of the u1, s1 and m1 series: a preset has the same resources as the VM of the same name. The list displayed by the wizard is authoritative:
| Preset | CPU | Memory |
|---|---|---|
u1.medium | 1 | 4Gi |
u1.large | 2 | 8Gi |
u1.xlarge | 4 | 16Gi |
u1.2xlarge | 8 | 32Gi |
u1.4xlarge | 16 | 64Gi |
u1.8xlarge | 32 | 128Gi |
s1.small | 1 | 2Gi |
s1.medium | 2 | 4Gi |
s1.large | 4 | 8Gi |
s1.xlarge | 8 | 16Gi |
s1.2xlarge | 16 | 32Gi |
s1.4xlarge | 32 | 64Gi |
m1.large | 2 | 16Gi |
m1.xlarge | 4 | 32Gi |
m1.2xlarge | 8 | 64Gi |
m1.4xlarge | 16 | 128Gi |
m1.8xlarge | 32 | 256Gi |
The wizard does not preselect any preset: choose one to continue. Each option shows its resources, for example “u1.medium — 1 CPU / 4Gi”. If the list cannot be loaded, the wizard displays “The preset list could not be loaded. Try again later or contact support.”
A cluster created with a former preset (nano, micro, small, medium, large, xlarge or 2xlarge) keeps it and runs as before: the Edit form shows it as is and saves it unchanged. If a cluster's resources were set outside its preset, the form says so with the mention “(override)”.
The preset's memory caps the size of the dataset Redis can keep in memory. Custom CPU/memory resources are not offered in the console; contact support.
Quotas and cost
The wizard displays the Estimated cost and the cluster's impact on the project quotas. If the cluster exceeds the available quotas, the Next button stays disabled.
Besides the replicas, the quota counts the cluster's three sentinels, each with the CPU and memory of the chosen preset, without storage: a 3-replica cluster therefore reserves 6 times the CPU and memory of its preset.
| Parameter | Value |
|---|---|
| Replicas | 1 to 8 |
| Volume size | 1 to 4,096 GB per node, within the project quota; increase only after creation |
| Redis databases | Logical database 0 by default |
Further reading
- Overview: service presentation
- Quick start: create your first cluster